Lord Shiva, the third in the trinity is Shiva, also known as Maheshwar (the great Lord), Mahadeva (the great God), Shambhu, Harihara (in union with Vishnu), Pinaakdhari (bearer of the axe), Mritunjaya (conquerer of death), and represents destruction, austerity & the malignant forces of life.
He is also represented as Mahakala & Bhairava, the terrible as well as many other forms including Rudra (howler). In ancient vedic hymns. Rudra is the malignant God of storm and wind, & is also considered the god of death. Rudra fires arrows of sickness at gods. men and animals. He is the father of Maruts, who were occasionally called Rudras.
As Rudra, he is identified with the star Sirius (Sothis), and is a supreme hunter. His appearance and nature changed with the emergence of Hiduism, when he became a beneficent and beautiful God, the Lord of animals and the patron of the hunters.
His name changed to Shiva, and is since then one of the most prominent deities of Hinduism. Shiva is also the master of all beings of the underworld including demons (bhutas ), ghosts (pretas), and pishachas (flesh eaters) but his destructive activities are compensated by his attitude of favors to his devotees.
He is originator of music and dance (Nataraja - the Dancing Shiva is the symbolism of the dance called Tandava), creator of grammar (vyaakrana), inventor of Yoga & a perfect householder as well as ascetic.